The present invention generally relates to digital processor apparatus and more particularly to digital microprocessor apparatus using MOS (metal-oxide semiconductor) LSI (large scale integration) technology. While the preferred embodiments are described with respect to an MOS LSI microprocessor, it will be understood by those of ordinary skill in the art that the invention is applicable generally to digital processing.
A microprocessor system typically includes a central processor unit (CPU), memory subsystem and input/output subsystem to permit the system to communicate with the outside world.
More detailed descriptions of prior art microprocessors are found in "Microprocessor," McGraw-Hill Yearbook of Science and Technology 1974, McGraw-Hill, Inc., New York, 1974, pp. 272-275; "Components: microprocessors galore," IEEE Spectrum, January, 1976, pp. 50-56; "Self-contained microcomputers ease system implementation," IEEE Spectrum, December, 1974, p. 53; and "Computer Interfacing: Anatomy of a Microcomputer," Computer Design, February 1976, pp. 129,130. All of the above citations are hereby incorporated by reference.